code: def __init__(cls, *args, **kwargs):
      cls.__instance = None
      super(_TzSingleton, cls).__init__(*args, **kwargs)
  
file_path: catboost/contrib/python/python-dateutil/py3/dateutil/tz/_factories.py
imports: from datetime import timedelta
  import weakref
  from collections import OrderedDict
  from six.moves import _thread
label_desc: Use image node_id 1 to create a new _TzSingleton object from inherited base classes: type with example: obj = _TzSingleton(cls)